PHILADELPHIA (CBS) — US senator Bob Casey D-Pa.) is still hoping a government shutdown can be avoided. But if it can’t, he says, it will be a great victory for the Republican right.

Pennsylvania’s senior senator says he has already compromised on two major issues in the budget process, but that doesn’t seem to matter in the current climate.

“The problem is the extreme right is driving the train, at least in the Congress. They are running the Republican side of the Senate, and they are running the House,” Casey said today during a brief stop at the 30th Street Amtrak station in West Philadelphia.

Casey says tens of thousands of Pennsylvanians, from federal employees to military personnel, won’t get paid in a shutdown.

“We have about 71,000 federal employees who could be furloughed,” he said. “When we talk about the military, tens of thousands of military families or civilian employees at military bases could be affected.

“It’s real simple to calculate who wins and who loses,” he added. “The middle class loses for sure, and the economy loses, and the far right would achieve a great victory.”

But nevertheless, Casey insists, it will not stop implementation of Obamacare.